function $(id){return document.getElementById(id)}
var divli = document.querySelectorAll("#iot-div5>div");
$("iot-div5").style.width = $("iot-div1").offsetWidth+'px';
let getwinwidth = function(){
    $("iot-div5").style.width = $("iot-div1").clientWidth+'px';
}
window.addEventListener('resize',getwinwidth);//监听窗口大小变化